Which of the following is listed as an additional hypernatremia cause?

• A. Severe dehydration
• B. Cushing's disease
• C. Burns
• D. Acute diarrhea

Answer: (A)

Hypernatremia arises when free water loss exceeds sodium loss, concentrating the serum sodium. Severe dehydration represents a large amount of water loss, so the sodium concentration rises, making it a clear additional cause. The other options don’t fit as directly: acute diarrhea often leads to isotonic loss or even hyponatremia rather than hypernatremia; Cushing's disease tends to alter fluid balance with possible sodium retention rather than concentrating sodium; burns cause fluid loss through the skin and can contribute to hypernatremia, but the strongest and most typical example among these is severe dehydration.